Re: [PATCH] Fix warning due to format mismatch for field width argument to fprintf()

From: Ben Hutchings <ben@decadent.org.uk>
To: Heiko Thiery <heiko.thiery@gmail.com>, netdev@vger.kernel.org
Subject: Re: [PATCH] Fix warning due to format mismatch for field width argument to fprintf()
Date: Sun, 16 May 2021 22:40:09 +0200	[thread overview]
Message-ID: <df0269f3bae01c37a7dbeaa4a8bb4b3fd0277d24.camel@decadent.org.uk> (raw)
In-Reply-To: <CAEyMn7ap3RL_oh0ucerH9POP+S4VGKfULhJQSb3AVeNFjR4VZw@mail.gmail.com>

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On Sun, 2021-05-16 at 20:11 +0200, Heiko Thiery wrote:
> Hi all,
> 
> Am Sa., 15. Mai 2021 um 09:59 Uhr schrieb Heiko Thiery <heiko.thiery@gmail.com>:
> > 
> > Added Ben's other mail addresses.
> > 
> > Am Sa., 15. Mai 2021 um 08:49 Uhr schrieb Heiko Thiery <heiko.thiery@gmail.com>:
> > > 
> > > bnxt.c:66:54: warning: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 3 has type ‘unsigned int’ [-Wformat=]
> > >    66 |   fprintf(stdout, "Length is too short, expected 0x%lx\n",
> > >       |                                                    ~~^
> > >       |                                                      |
> > >       |                                                      long unsigned int
> > >       |                                                    %x
> > > 
> > > Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
> > > ---
> > >  bnxt.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/bnxt.c b/bnxt.c
> > > index b46db72..0c62d1e 100644
> > > --- a/bnxt.c
> > > +++ b/bnxt.c
> > > @@ -63,7 +63,7 @@ int bnxt_dump_regs(struct ethtool_drvinfo *info __maybe_unused, struct ethtool_r
> > >                 return 0;
> > > 
> > >         if (regs->len < (BNXT_PXP_REG_LEN + BNXT_PCIE_STATS_LEN)) {
> > > -               fprintf(stdout, "Length is too short, expected 0x%lx\n",
> > > +               fprintf(stdout, "Length is too short, expected 0x%x\n",
> > >                         BNXT_PXP_REG_LEN + BNXT_PCIE_STATS_LEN);
> 
> This does not solve the issue. The provided patch only works on 32bit
> systems. It seems there is a problem with 32bit vs 64bit.

It looks like the type of BNXT_PXP_REG_LEN + BNXT_PCIE_STATS_LEN will
be size_t, so the correct format is "%zx".

Ben.

-- 
Ben Hutchings
Sturgeon's Law: Ninety percent of everything is crap.

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